metcalf



July 2, 1929,

H. E. METCALF TUBE GRID AND METHOD MAKING SAME IN VE/Vv-OR,

Patented .uly 2, 1929.

HERBERT E. METCALF, OF SAN LEANDRO, CALIFORNIA, ASSIGNOR TO THE MAGNAVOX COMPANY, OF SAN FRANCISCO, CALIFORNIA, A CORPORATION OF ARIZONA.

TUBE GRID AND METHOD OF MAKING SAME.

Application filed.` May 18,

'Ihis invention relates to an improved grid for radio vacuum tubes and to a method of manufacturing such grid. The primary object ot the invention is to provide such an improved grid and to manufacture the same by a simpler and cheaper method than has been used heretofore.

In the ordinary radio vacuum tube the grid comprises a plurality ot wires strung horizontally between two spaced vertical posts or a wire spiral hanging in a vertical positionv within the tube. The filament is positioned in the opening extending longitudinally and vertically through the grid. A grid of the :first type ust mentioned is ordinarily `formed on the posts when assembling the two parts together. My invention contemplates the manufacture of a grid as an independent article, whereby the same can thereafter be assembled bodily in the tube.

More specifically my improved method comprises the weaving of the grid-forming wires into a sheet of a pattern which can thereafter be cut up into pieces and readily formed into grids of the desired configura tion. A further obj ect of my invention is the provision of such an improved method and the improved grid made thereby.

In the accompanying drawing I have illustrated one specific embodiment of my invention, but it will be understood that the invention can be otherwise embodied and that the drawing is not to be construed as defining or limiting the scope of the invent-ion, the claims appended to this speciiication being relied upon -for that purpose.

Referring to the ligures of the drawing,

Fig. l is a tace view of a portion ot a woven wire screen or sheet of a pattern adapting the same to be used in m anutacturing my improved grids.

Fig. 2 illustrates a portion out from the Vsheet and from which a grid is formed.

Fig. 3 is a perspective view illustrating a grid formed from the wire piece shown in .F ig. 2. v

1925. Serial No. 30,947.

In the drawing, l indicates a plurality of uniformly spaced wires which are tied together and formed into a sheet by spaced groups 2 ot wires extending in a relatively right angular direction thereto. This wire sheet is thereafter severed in relatively right angular directions to form the same into independent grid-forming pieces like that Vshown in Fig. 2. To form these pieces the sheet ot Fig. l is cut longitudinally through the center ot the alternate wire groups 2, as for example on the line a-a. These resulting strips are then severed into lengths equal to the length of the grid it is desired to make. These pieces are then formed into a grid of the shape shown in Fig. 3, the two ends ot' the strip being secured together in any manner desired.

The completed grid shown in Fig. 3 is the piece shown in Fig. 2, bent about the central portion b and having the ends c thereof secured together. The wires l form the sides of the grid and the edges d are formed from the groups 2 of wires heretofore described.

Having thus described my invention, what I claim as new and desire to secure by Let-- ters Patent is:

l. A method of manufacturing grids consisting of weaving wires in relatively trans` Vverse directions in a manner forming a sheet having spaced wires running in one direction and tying them together by relatively spaced groups of wires woven therethrough in a relatively transverse direction, and forming a portion of such sheet into an oblong tubular grid having the sides thereotl formed of the said spaced wires and the ends ot the sides formed of the said groups of wires.

2. A grid for vacuum tubes, comprising an elongated tubular member formed of parallel wires extending at right angles to the longitudinal axis of the grid, and stitli'ening wires folded into the irst-mentioned wires at the narrower sides of the grid and extending parallel to the longitudinal axis of the grid.

HERBERT E. METCALF. 

